You would do terrible. There is nothing you can learn from a movie that could be of any use in combat.
Even worse, if you start mimicking the tactical behavior and movements of a movie soldier, you would get yourself killed very quickly.
In the movies, soldiers risk way too much. They almost never retreat, never run away, and always want to fight it out, even when they are completely outnumbered.
Furthermore, the way Hollywood artillery and other weapons are working has nothing to do with real combat. RPGs for example, fly much faster in reality than they do in the movies (one of the flaws in “Black Hawk Down”) and there is no time to yell at your buddies before you get hit.
An easy way to get yourself killed is to attack an enemy tank with inadequate weapons (from the movie “Saving Private Ryan”. Picture: tigerdroppings)
On the other hand, the beach scene of “Saving Private Ryan” is quite realistic. It demonstrates that you’ll most likely die if you don’t take cover. Unfortunately, the longer this movie goes on, the more unrealistic it gets, and at the end, there is a squad of GIs fighting alone against an armored company of Waffen-SS soldiers and the Americans win!
Good luck to everyone who wants to put some explosives on a driving enemy tank! You’d better not do that.